Presetting of Overstressed Springs
Helical Spring Design Resources - Spring Manufacturing
In Newcomb's technical bulletin, "Permanent Set", we discussed conditions where springs take a set or "shortens up" under load due to high stressed conditions. In this bulletin we cover a method that is referred to in the industry as "Presetting." This is an added operation that allows the design to obtain allowable elastic limits and thus greater load capacity at higher load lengths otherwise not obtainable.
Presetting consists of coiling the spring to a longer length than the ultimate desired free length and then compressing it beyond its elastic limit. Presetting allows the use of higher design stresses with the added cost of the secondary operation. Some of this added cost, however, is sometimes offset by using less material within a given envelope.
Working with your springmaker can often eliminate the need to preset springs; but, if necessary, cost can be reduced by working together to develop the best design possible.
Please contact the Newcomb Spring facility nearest you for more information on presetting spring and other considerations of spring design.